This invention relates to a floppy disk drive control apparatus for controlling a floppy disk drive for driving a floppy disk loaded in the floppy disk drive.
In the manner known in the art, a floppy disk drive (which may be abbreviated to xe2x80x9cFDDxe2x80x9d) is a device for carrying out data recording and reproducing operation to and from a magnetic recording medium of a floppy disk (which may be abbreviated to xe2x80x9cFDxe2x80x9d) loaded therein. In addition, such a floppy disk drive is loaded in a portable electronic device such as a laptop personal computer, a notebook-size personal computer, a notebook-size word processor, or the like.
The floppy disk drive of the above described type comprises a magnetic head for reading/writing data from/to the magnetic recording medium of the floppy disk, a carriage assembly for supporting the magnetic head at a tip thereof with the magnetic head movably along a predetermined radial direction to the floppy disk, a stepping motor for moving the carriage assembly along the predetermined radial direction, and a spindle motor for rotatably driving the magnetic recording medium with the floppy disk held.
Conventionally, control of the floppy disk drive is carried out by a host device such as a personal computer, a word processor, or the like. The host device is herein called the SET side, and the floppy disk drive itself is herein called the FDD side.
In the manner which will later become clear, a conventional FDD control apparatus comprises a part loaded in the SET side and a part loaded in the FDD side. The SET side is loaded with a device driver and a floppy disk controller (FDC). On the other hand, the FDD side is loaded with an FDD controller connected to the floppy disk controller, a stepping motor driver for driving the stepping motor, a spindle motor driver for driving the spindle motor, and a reading/writing control circuit for controlling reading/writing of data via the magnetic head. The stepping motor driver, the spindle motor driver, and the reading/writing control circuit are connected to the FDD controller.
As described above, in the conventional FDD control apparatus, the control of the floppy disk drive is carried out by the SET side. As a result, a torque required for the stepping motor is determined by a control method of a seek operation (operation of the stepping motor) in the SET side. In other words, a step signal for driving the stepping motor is supplied from the SET side to the stepping motor. The step signal is a pulse signal comprising a train of pulses having a pulse period of a predetermined time interval which is equal to, for example, three milliseconds. Conversely, it is impossible for the floppy disk drive to fumble or deal with the pulse period of three milliseconds. Accordingly, in prior art, it is impossible to use a step signal having a pulse period which is longer than three milliseconds and it is impossible to decrease the torque of the stepping motor to less than the torque which is uniquely determined by three milliseconds. In addition, it is noted that the longer the pulse period of the step signal becomes, the higher the torque of the stepping motor becomes.
When the stepping motor has a high resistance, a consumed current in the stepping motor decreases and the torque of the stepping motor decreases. As a result, in order to ensure performance of the seek operation in the floppy disk drive, the resistance of the stepping motor has an upper limit level which is set to about 20xcexa9. In addition, to increase the resistance of the stepping motor, for example, a thin winding may be used or the number of turns of a winding may be increased.
In other words, it is preferable that the consumed current in the stepping motor is small. However, when the stepping motor has a low torque, there is disadvantage in the manner which will presently be described.
Firstly, it is difficult to carry out operation on starting of the stepping motor. This is because, in the manner known in the art, a motor generally requires the highest torque on starting. Secondarily, it is difficult to carry out a seek operation in a state where the floppy disk is not loaded or inserted in the floppy disk drive in the manner which will later be described in conjunction with FIGS. 3A and 3B.
It is therefore an object of the present invention to provide a floppy disk drive apparatus which is capable of ensuring performance of a seek operation in a floppy disk drive even when the stepping motor has a low torque.
It is another object of the present invention to provide a floppy disk drive apparatus which is capable of reducing a consumed current in the stepping motor.
Other objects of this invention will become clear as the description proceeds.
The present inventors zealously studied how to ensure performance of a seek operation in the floppy disk drive even when the stepping motor has a low torque. As a result of their studies the present inventors reached the conclusion that it is difficult to ensure performance of the seek operation in the floppy disk drive when the control part for controlling the floppy disk drive or the floppy disk controller (FDC) is loaded in the SET side in the manner of the conventional FDD control apparatus.
On describing the gist of this invention, it should be understood that a floppy disk drive control apparatus controls a floppy disk drive (FDD) for driving a floppy disk loaded in the floppy disk drive. The floppy disk drive control apparatus comprises a part loaded in a host side and a part loaded in an FDD side. According to this invention, a control part for controlling the floppy disk drive is disposed in the FDD side. That is, this invention is characterized in that the control part for the floppy disk drive is disposed in the FDD side, whereas conventionally control part for controlling the floppy disk drive is disposed in the host side or the SET side.
In the floppy disk drive control apparatus, the control part may include a floppy disk controller (FDC). In addition, inasmuch as the control part for the floppy disk drive is disposed in the FDD side, the host side preferably may be loaded with a connector called a universal serial bus (USB) connector that is connected to the control part. In the manner known in the art, the universal serial bus (USB) is a personal computer-oriented interface specification for connecting peripheral units. When the floppy disk drive comprises a stepping motor, the control part desirably may include a memory for storing a program for adjusting a step timing of the stepping motor.